1. Field of the Invention
The invention relates to a method for making synthetic leather, more particularly to a method for making synthetic leather that is stretchable in longitudinal and transverse directions.
2. Description of the Related Art
A conventional method for making synthetic leather includes the steps of applying a polyurethane resin on an unstretchable substrate, wet foaming the resin, separating the foamed resin from the substrate, and adhering the foamed resin to an elastic substrate. However, the method can not be carried out in a continuous process. Furthermore, when the foamed resin is adhered to the elastic substrate, it is difficult to control tension therebetween, which in turn results in an uneven tension distribution of the resultant product.
Another conventional method for making synthetic elastic leather includes the steps of adhering an elastic substrate containing elastic fibers to an unstretchable base fabric, conducting a wet process of the synthesis leather, and stripping the base fabric from the elastic substrate. However, the processing procedure of this method is relatively complicated, and is thus time-wasting and costly.
Although synthetic leather is broadly used in various applications, such as clothes, shoes, furnitures, automobiles, etc., the conventional synthetic leather is not stretchable in longitudinal and transverse directions, which will make the user feel uncomfortable and/or restrict the application thereof.
Therefore, the object of the present invention is to provide a method for making synthetic leather that is stretchable in longitudinal and transverse directions.
Accordingly, the method for making synthetic leather according to this invention includes the steps of:
preparing a knitted substrate having a longitudinal direction and a transverse direction transverse to the longitudinal direction, the knitted substrate being stretchable in the longitudinal and transverse directions;
positioning two opposite sides of the knitted substrate along the longitudinal direction respectively on two conveyer chains, and advancing the knitted substrate without tensioning the substrate along the longitudinal direction; and
forming a coating on the knitted substrate by applying a polyurethane solution on the knitted substrate.